(Bloomberg) -- Nassim Nicholas Taleb has a message for investors. Prepare for a painful return to reality.

“Disneyland is over, the children go back to school,” the author of “The Black Swan” said. “It’s not going to be as smooth as it was the last 15 years.”

A generation of near-zero interest rates triggered a monumental series of asset bubbles and turbocharged inequality, Taleb said Monday at an event in Miami hosted in part by Universa Investments, the hedge fund firm that he advises. Investors are largely unequipped for a high-interest world as the Federal Reserve raises rates to levels more compatible with history, he said.

Taleb described a generation of investors who over the past 15 years forgot the importance of cash flow as the financial crisis unleashed a wave of easy money. He said crypto was indicative of the naivete in markets after years of low rates.

“All these years, assets were inflating like crazy,” Taleb said. “It’s like a tumor, I think is the best explanation.” 

Taleb identified the “tumors” as everything from Bitcoin to real estate prices that have ballooned under a low interest regime. He estimated such “illusionary wealth” at more than half a trillion dollars as he predicted the Federal Reserve is going to keep raising rates.

He also cited Twitter as an example of cash-burning companies that will struggle under a new monetary regime. While he didn’t call out Elon Musk by name, he cited the Twitter acquirer as a “brilliant financial mind” who has been given a harsh lesson in cash flow. “It doesn’t rain money anymore,” Taleb said.  

His comments come the same week that his long-time colleague and protege, Universa Chief Investment Officer Mark Spitznagel, warned investors that the market is a “tinderbox-timebomb” that could rival the unraveling of the 1930s era Great Depression given the boom in debt. 

Read More: Black Swan Fund Manager Sees ‘Tinderbox-Timebomb’

Taleb is similarly gloomy.

“Things won’t be fine for a while,” he said. “We have the weirdest valuations in history.”

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